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OD Clutch Failure

Wednesday, October 1, 2014 - 07:00
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Premature overdrive clutch failure, with 45, 545 and 68 - RFE transmissions is a common complaint. 

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There are a few reasons for this which has been mentioned in previous Powertrain Pro articles. A worn solenoid switch valve and bore was one of the causes covered. A faulty line pressure sensor (transducer) was another. When these two items are not the cause, less common causes need to be considered and brought into view. 

Filter problems or other valve body issues such as worn check balls, pump and ring issues and seals to name a few. But when it comes to Dodge 6.7L diesels and the 68RFE, whether it is a 2500, 3500 or any other model, there is yet another common issue.

Many owners install some form of a tuner which may include a monitor that remains plugged into the ALDL. This monitor may provide information to the driver such as Turbo Boost, Vehicle Speed, Transmission and Engine Coolant Temperature (figures 7 and 8). When this program is installed, it does what it claims to do by increasing horse power. When it does, the apparent weakest link between the engine and the wheels is the Overdrive Clutch assembly. Without modifying the transmission, these babies can fry.

Ask Ralph at Alonzo’s Transmissions in Miami. He had a nightmare of a time with a 2007 Dodge Ram 3500 with the 6.7L Cummins Diesel that kept coming back to the shop. He put in a new valve body, converter pump and drums and still returned. Incorrect fluid level was considered and verified to be correct. The tuner had the ability to return the PCM to factory settings but that didn’t stop it from returning. This apparently is a known problem in the trucking world with performance diesel engines as SunCoast Diesel Transmissions and Converters in Fort Washington Beach Florida makes a modified kit to resolve this issue.

The company has several CNC machines and they produce all their own modifications that are known and used worldwide. 

The 68RFE M3GA Drum for example is billet made with larger diameter apply areas to increase holding capacity. They also have a kit with a modified pressure regulator valve and spacer plate. By raising line pressure and modifying the drum, a solution is available for those fighting the same problem. It’s not cheap but when it comes to quality performance parts are they ever?


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